Telephone exchange an electronic boon to the mankind serving from decades for communication. Its one of the best combination of Analog, Digital & Mechanical circuits. The exchange technology has undergone many phase of changes ever since its existence. ST2657 Automatic Telephone Exchange Training / EPABX System forms the basic of telephone exchanges, EPABX technology study. Both manual and automatic switching can be performed. The functional blocks provides easy understanding of the working of the system. Visualizations of the switching and detections makes it unique. A DTMF Telephone Trainer is supplied for better understanding of Telephony.

Technical Specifications

• Number of inputs : 2 Trunk / Direct Lines.
• Number of extension : 4 Lines.
• Technology : Cross Point Space Division (Microprocessor based)
• Standard Features : Tones such as Dial, Busy, Ring etc. Dialing - DTMF and Pulse (Ratio 10pps )
• Program Memory : 64 Kb EEPROM
• Loop Resistance : Extension -600 Ohms, Co-line-1200 Ohms.
• Cross Talk Attenuation : >70 dBm
• Test Points : More than 25 Nos.
• Power supply : 230 V ±10%, 50 Hz / 60 Hz on request
• Power Consumption : 40.25 VA (approx.)
• No. of switched faults : 8
• No. of test points : 38
• Features that can be set : Line Hunting, Direct Access to trunk line, Redial, Line Status Indication, Automatic call back, Do Not Disturb, Call Transfer, Call Pick Up, Direct Access Trunk Call Forwarding, Call parking,
• Conference, Hot line System, Extension Privacy, Call Transfer, Barge in
• Fuse : 2 Amp

Included Accessories

1. Telephone Instruments : 3 Nos.
2. Telephone Trainer : 1 No.
3. Extension line cords : 4 Nos.
4. Software CD : 1 No.
5. AC Adaptor : 1 No.

• Easy understanding of various units
• Use of functional blocks than traditional circuitry
• Study of various detection phenomena's
• Detailed circuit study
• LED visualizations
• Performing manual switching
• Study of switching Phenomena
• Study of traffic units
• Switched faults
• CD containing Working Presentation
• Supplied with DTMF Telephone Trainer

Experiments that can be performed

1. Generation of various Tones Dial, Tone, Busy Tone, Ring Back Tone.
2. Measurement of Ring generation.
3. Study & Analysis of Cross point Space Division switching.
4. Study & Analysis of Manual switching.
5. Analysis of Pulse / DTMF dialing from telephone (Extns).
6. Measurement of Relay & Ring control signals.
7. Study & analysis of ON / OFF hook, Ring detection.
8. Study of power supply.